Incrementing and Decrementing - Just Trying to Understand
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WidmarkRob wrote:
Did I understand that right?
:laugh: No, it's a bit badly explained: it isn't referring to the whole expression, just the little "x++" or "++x" bit - it doesn't matter if you do prefix or postfix, the value of x is the same after them both. That doesn't mean it is unchanged, just that it doesn't matter which you do, they both affect the variable in the same way.
y = ++x + 10;
y = x++ + 10;
What it's saying is that if x started at 100, in both cases it will be 101 afterward, despite y getting a different value each time.
WidmarkRob wrote:
So, now the variable y never really changes in the first expression.
y does get changed by the postfix increment, it's just that the changed value is overwritten with the total from the whole expression.
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
Aaaahhhh... maybe I get it now, maybe… Give me a simple exercise… Maybe just barely, a little bit tiny bit harder than what I've been working with to see if I understand right. I'll try to do it in my head really quick before I go and open Visual C# Express. Your last line: "y does get changed by the postfix increment, it's just that the changed value is overwritten with the total from the whole expression." Kind of sort of little a lightbulb in my head. D'oh My Coding Journey
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Aaaahhhh... maybe I get it now, maybe… Give me a simple exercise… Maybe just barely, a little bit tiny bit harder than what I've been working with to see if I understand right. I'll try to do it in my head really quick before I go and open Visual C# Express. Your last line: "y does get changed by the postfix increment, it's just that the changed value is overwritten with the total from the whole expression." Kind of sort of little a lightbulb in my head. D'oh My Coding Journey
:laugh: I like lightbulb moments! Try this:
int x = 10;
int y = 100;
int z = ++x + (y++ * x);
Console.WriteLine("x = {0}, y = {1}, z= {2}", x, y, z);If you can work that out in your head, you are doing very, very well! Normally, they don't get that complex - they are generally used for array indexes as such like:
byte[] data = File.ReadAllBytes(@"D:\Temp\MyFile.txt");
int i = 0;
do
{
if (data[i++] == 'x')
{
break;
}
} while (i < data.Length);The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
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:laugh: I like lightbulb moments! Try this:
int x = 10;
int y = 100;
int z = ++x + (y++ * x);
Console.WriteLine("x = {0}, y = {1}, z= {2}", x, y, z);If you can work that out in your head, you are doing very, very well! Normally, they don't get that complex - they are generally used for array indexes as such like:
byte[] data = File.ReadAllBytes(@"D:\Temp\MyFile.txt");
int i = 0;
do
{
if (data[i++] == 'x')
{
break;
}
} while (i < data.Length);The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
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x = 10 y = 100 z = 1112 lightbulbs still on? My Coding Journey
I think you had a brief power cut...:laugh:
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
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I think you had a brief power cut...:laugh:
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
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:laugh: I like lightbulb moments! Try this:
int x = 10;
int y = 100;
int z = ++x + (y++ * x);
Console.WriteLine("x = {0}, y = {1}, z= {2}", x, y, z);If you can work that out in your head, you are doing very, very well! Normally, they don't get that complex - they are generally used for array indexes as such like:
byte[] data = File.ReadAllBytes(@"D:\Temp\MyFile.txt");
int i = 0;
do
{
if (data[i++] == 'x')
{
break;
}
} while (i < data.Length);The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
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my electrons, neutrons and protons all turned into morons My Coding Journey
Maybe one or two of them! :laugh:
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
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Maybe one or two of them! :laugh:
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
Ah S4!T... *Siiiiigh* Let me look at it again… This time I will type it out so you can see how I get my answers. My Coding Journey
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Maybe one or two of them! :laugh:
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
before I go look at it again… Did I get x and y right? Is it z, that I got wrong? My Coding Journey
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z = 1012 ???:confused::confused::confused: My Coding Journey
Ok, let's look at it (though it's a PITA to work out, I admit) and substitute the values:
int x = 10;
int y = 100;
int z = ++x + (y++ * x);++xmeans "add one toxand use the new value", soxbecomes11, and the calculation becomes
z = 11 + (y++ * x)
y++means "Add one toyand use the old value", soybecomes101, and the calculation becomes
z = 11 + (100 * x)
- We only have
xleft to worry about, so get the current value of it (which is 11 because we changed it in step 1) and the calculation becomes
z = 11 + (100 * 11)
Which is
z = 11 + 1100
Or
z = 1111
So the final result is:
x = 11, y = 101, z= 1111
This is a lot more complex than anything you should have to meet in "real life" (hence the discussion above about hitting people who do that kind of thing and why C++ will give you different results)
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
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Ok, let's look at it (though it's a PITA to work out, I admit) and substitute the values:
int x = 10;
int y = 100;
int z = ++x + (y++ * x);++xmeans "add one toxand use the new value", soxbecomes11, and the calculation becomes
z = 11 + (y++ * x)
y++means "Add one toyand use the old value", soybecomes101, and the calculation becomes
z = 11 + (100 * x)
- We only have
xleft to worry about, so get the current value of it (which is 11 because we changed it in step 1) and the calculation becomes
z = 11 + (100 * 11)
Which is
z = 11 + 1100
Or
z = 1111
So the final result is:
x = 11, y = 101, z= 1111
This is a lot more complex than anything you should have to meet in "real life" (hence the discussion above about hitting people who do that kind of thing and why C++ will give you different results)
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
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okay, it is relieving I was only off by one My Coding Journey
Welcome to the "I hit people who do that" club - your laminated membership card is in the post... :laugh:
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
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I know - BUT, why the hell would anyone write such a monstrosity. ;P Also, as it was clearly a beginner question, I was trying to simplify. So you get 10/10 for correctness but 2/10 for being clear for the sake of the OP.. :omg:
wait a minute? Who gets 10/10 for being correct? OG or Me? My Coding Journey
